椭偏法测光栅参数的可行性理论研究

提出一种新的光栅测试方法-利用椭偏仪测量光栅的基本参数，同时将求解优化问题的正单纯形法用来反演光栅的椭偏方程。首先假设一种光栅模型，计算出不同入射角的椭偏参数（△,φ),然后加入偏差量不同的高斯噪声，把加入噪声后的值（△m,φm）作为模拟测量值，采用正单纯形法进行求解，验斑点得知由这种方法求得的光栅参数接近假设的光栅参数值。反演结果表明，在扩大搜索范围时，仍可以在一定精度范围内得到准确解，这就在理论上验证了用椭偏仪测试光栅参数的可行性。     

透射光谱法测光栅参数的可行性

利用透射光谱,结合正单纯形法来反演折射率调制光栅参数,首先利用光栅衍射傅里叶模式理论及RTCM算法得出在200nm~900nm波长范围内的透射光谱曲线,从上取5个点,作为理论计算值; 其次,在上述曲线上加入偏差不同的高斯噪声,以模拟透射光谱的测量曲线,再从每条曲线上各取5个对应点,获取模拟测量值;然后,假定光栅参数的初始值,代入评价函数,用正单纯形法不断进行迭代反演,得到光栅参数的计算模拟结果。此方法简单、快速、精确。     

用透射光谱法测光栅参数的数值模拟

本文基于光栅的严格理论,提出结合透射光谱和优化算法来测量光栅参数的新方法,首先,利用傅立叶模式理论和反射透射系数递推算法(RTCM) ,计算出在2 0 0 -90 0nm波段内的理论透射光谱图,通过在上面叠加不同偏差的高斯噪声来模拟光栅的实际测量曲线,接着在模拟曲线上任取若干个点作为实验测量值,最后利用优化算法进行反演搜索,找到待测光栅的结构参数。文中我们选择了三种类型的光栅对该法进行数值上的模拟,其结果是成功的。该法可能会给光栅参数的测量指明一条新的途径。     

毫米波椭偏测量法的数值模拟研究

介绍了一种新型的毫米波椭偏法,可以用来测量介质材料的介电常数和厚度.通过分析入射波波长和入射角的不同取值对实验结果的影响,给出了入射波波长和入射角的取值范围,同时对介电常数、厚度与椭偏参数之间的关系进行了数值模拟研究.研究结果表明,由椭偏参数经数值计算反演出的介电常数、厚度通常会出现多值的情况.但对大多数的介质薄膜而言,却可以通过该方法求出唯一确定的介电常数与厚度,表明了毫米波椭偏法在介质参数测量上的可行性.     

红外吸收薄膜复数折射率的计算

本文利用最优化数值计算方法中的单纯形法,通过对薄膜厚度、反射率、透射率的测量得出红外吸收薄膜的复数折射率计算程序,并给出了应用实例。实践证明,较之其它计算复折射率的方法,如椭偏谱测量法,本方法是有效和准确的。     

基于椭偏成像光路和表面等离子体共振效应的金属薄膜参数测量方法研究

提出了一种基于椭偏成像光路和表面等离子体共振效应的金属薄膜参数测量方法,在椭偏成像光路中采用p偏振光在金属薄膜与空气界面产生表面等离子体共振效应,利用不产生表面等离子体共振效应的s偏振光消除背景光的影响,得到表面等离子体共振吸收环垂直方向的归一化反射率曲线,数值拟合获得待测金属薄膜的薄膜参数,这种方法不需要求解椭偏方程,数据处理过程简单,求解速度快。实验中,基于该方法的测量结果与标准椭偏仪的测量结果基本一致,很好地验证了该方法的有效性。     

射频溅射生长的氮化硅膜的椭偏光谱测量

本文提出一种处理数据的方法,以解决利用两个椭偏测量值ψ、△,求解两个以上未知参量,得到了在本实验条件下生长的氮化硅膜的实在折射率及其色散,以及氮化硅膜的生长率.实验结果还表明,氮化硅与硅衬底间存在一界面层,     

光栅衍射激光告警接收机的探测性能分析

灵敏度和信噪比是激光告警接收机两个重要的性能指标,它们直接影响系统的探测性能和抑制噪声的能力.根据信号统计检测理论,提出了一种计算光栅衍射型激光告警接收机灵敏度和信噪比的方法.首先,对激光信号和系统的内、外噪声进行了系统分析.然后,基于阈值探测理论和奈曼一皮尔逊准则,通过引入探测概率因子和虚警概率因子,求解出以激光信号电流为变量的方程,得到了灵敏度和信噪比的一般表达式.最后,结合该方法利用自行研制的基于正弦光栅衍射型激光告警接收机的实际参数对探测灵敏度和信噪比进行了数值模拟和实验验证,得到0.532 μm激光入射时的探测灵敏度计算值为1.95 mW/cm2,实验值为2.55 mW/cm2.不同入射波长之间的信噪比差异较小,表明该分析方法可以对激光告警接收机的信噪比进行评估.     

频谱傅立叶法测量偏振模色散研究

对频谱傅立叶分析法测量偏振模色散进行了理论、模拟与实验研究。利用这种方法,分别对由一段、两段、三段保偏光纤组成的PMD模拟器进行了数值模拟．并对保偏光纤、单模光纤以及商用模拟器进行了实验测量,得到了很好的结果。将这种方法和波长极值计数测量法进行了比较,研究表明,由于考虑了偏振模色散的统计特性,频谱傅立叶分析法适于测量强耦合光纤。     

穆勒椭偏标定方法中LM算法研究

依据穆勒椭偏测量方法中偏振光的传输方式,提出了一种椭偏系统中光学元件参数的定标方法。通过建立出射光强关于起偏器和检偏器透光轴方位角、旋转补偿器方位角和相位延迟的非线性最小二乘模型,用列文伯格?马夸尔特（Levenberg-Marquardt,LM）算法对初始参数进行迭代。求解出光学元件参数的精确值,从而实现对元件的定标。通过仿真实验,利用已知穆勒（Mueller）矩阵且标定值为(24.90±0.30) nm的SiO₂/Si标准样片,基于LM算法迭代计算光强值的残差平方和。实验可得当迭代次数为50次时,残差平方和收敛到最小值0.24;与传统多点标定法进行对比试验,验证了基于LM算法求解光学参数的可行性;用标定值为(91.21±0.36) nm的SiO₂/Si标准样片进行验证,得到膜厚的计算值为91.53 nm,相对误差为0.35%。结果表明:在穆勒椭偏系统参数标定中,LM算法具有收敛速度快,计算精度高等优点。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.